In this P01, investigators involved in 4 of the largest studies of breast cancer in women of African ancestry (AA) are collaborating to combine research hypotheses, data, samples, and expertise, and to harness the expertise of additional scientists, to discover risk factors that predispose AA women to early-onset aggressive breast cancer. This ambitious collaboration will require extensive coordination for the P01 to be successful. Administrative Core A, led by the 3 P01 PIs, will ensure that the Program Project runs smoothly, that the Projects meet their timelines and aims, and that the Cores provide the necessary support for each of the Projects to be successful. The Core will coordinate all organizational aspects of the P01, including maintaining matrix communications among the investigators and key personnel in each of the Projects and Cores, planning and conducting regular In-person meetings of the P01 investigators and with the External Advisory Board, and fiscal management of the overall P01 and disbursement of subcontract funds. Importantly, the Core will be responsible for evaluating and monitoring productivity, executing deadlines, and mediating any issues or problems that may arise. Core A will be based primarily at Roswell Park Cancer Institute (RPCI), in close coordination with the other 2 PI institutions, Boston University (BU) and the University of North Carolina at Chapel Hill (UNC), and with Dr. Kolonel at the University of Hawaii. The Administrative Core will ensure that the scientific and fiscal management of the study is rigorous, and provide a resource for coordination of the research through the Projects and Cores. Core A is essential to maintain the continuity of the Program Project. Without the pooling of expertise and coordination of tasks and duties, there would be multiple instances of duplication by Projects.